Search Documents

[ ]

Jan 1, 1938

By S. Chander

A review of the published literature on the mechanism of depression of sulfide minerals shows that a unified theory is not yet available. Various mechanisms that have been postulated include competition between depressants and collectors to adsorb at the surface sites, creation of thermodynamic conditions nonconducive for formation of a metal collector salt, or formation of a hydrophilic coating on the surface. The hydrophilic coating may or may not effect the adsorption of collectors. In another mechanism, the depressant may participate directly in oxidation/reduction reactions between collectors and sulfide minerals. Examples from the literature highlight oxidation/reduction effects in the depression of sulfide minerals.

Jan 1, 1986

By Thamyres Moura Lima

O presente trabalho, traz a analise eletroquímica, curvas de polarização,das ligas Ti-35Nb-xTa (x = 0; 2,5; 5,0; 7,5)Ta (% em peso) anodizadas, a um potencial de 20V e 1hora e sem anodizar , para verificar o aumento da resistência a corrosão dessas ligas. O meio ao qual os ensaios foram realizados foi o sfb ( fluido corpóreo simulado).Obtendo como resultado que as ligas anodizadas apresentam maior resistênciaa corrosão nesse meio. A liga sem adição de tântalo obteve menor densidade de corrente, assim tendo uma maior resistência a corrosão após anodizada o que não ocorre sem a anodização.

Oct 30, 2017

By G Cao, Y R. Cui, J X. Zhao, H P. Gui, G H. Wang, Z M. Wang, M M. Ren, B Li

Pyro-metallurgy is still the main process for lead production and a lot of lead direct smelting processes have been developed in recent years. All the processes will experience two steps in common. The first is the oxidisation of PbS to PbO and then reduction from PbO to Pb, furthermore, from ZnO to Zn. So, the composition of melts, especially the slag composition at reduction step change continuously. Up to now, there are few systematic results on the slag physical-chemical properties with its composition change. In this work, the typical lead direct smelting processes were analysed from theoretical and practical standpoints. The full-period slag composition and slag melting point change were compared. Especially, to the PbO and ZnO reduction steps, based on the full-period slag composition change, the slag properties were predicted. Based on dust composition and test results, the mechanism of Pb compound evaporation and its effect on practice and measurement of high PbO bearing slag physical-chemical property is discussed. It is suggested that to restrain the evaporation in practice and to obtain more accurate measurement results of physicochemical properties of smelting slag are the key problem not only to set high efficiency, energy saving process, but also to environmental pollution control.

Aug 21, 2024

By McGuckin P. H

The Cadjebut orebody is a MississippiValleyType (MVT) zinc-lead deposit, and is located approximately 80 km southeast of Fitzroy Crossing in the Kimberley region of Western Australia. It is one of five zinc rich orebodies discovered by BHP Minerals in the region.The participation in the Cadjebut Joint Venture is BHP Minerals limited (Manager), 58 per cent and Billiton Australia Limited, 42 per cent.The mineralisation is contained in gently dipping dolomitised limestone sediments (part of the Lennard Shelf carbonate sequence) with an orebody width of between 60 and 120 m and a strike length of approximately 3 km. The deposit consists of two thin, stratabound shallow dipping orebodies, one overlying the other, to provide discrete but not independent mining areas. The orebody contains approximately 2.1 million tonnes of recoverable ore at an approximate grade of 12 per cent zinc and four per cent Lead.

Jan 1, 1992

By Kareise G. J, Leung K

The McArthur River (HYC) deposit, located in the Northern Territory of Australia, was discovered by Mt Isa Mines Limited geologists in 1955. It is one of the largest sedimentary stratiform zinc-lead-silver deposits known. Previous attempts to exploit the deposit have been thwarted by its geographical location, the capital expenditure required to establish an operation and the fine-grained nature of the mineralisation. The steeply dipping western margin of the deposit is covered by up to 25 m of overburden, and lies beneath the McArthur River and its flood plain. Dips are eastward, with the eastern edge of the deposit at a depth of about 400 m below the surface. The average thickness of the deposit is 55 m, and it covers an area of about 1.8 by 1.3 km. Seven stratiform orebodies are interbedded with sedimentary breccia, tuff and poorly mineralised siltstone. Mineralisation consists of finely intergrown sphalerite and galena, hosted by pyritic siltstone of the middle Proterozoic McArthur Group. Selective underground mining of the lower orebodies will extract more than one million tonnes of ore per annum. The dip of the mineralisation demands that mining will be by way of apparent dip room and pillar. Declines will provide access and haulage, and wherever possible development will be in ore. Initially, haulage will be by trackless diesel powered trucks, but these will be replaced by a conveyer system. A single zinc-lead-silver concentrate will be produced from a simple flowsheet. This flowsheet has been developed in the laboratory and demonstrated during an extensive pilot plant campaign. A single stage SAG mill will be utilised to grind the ore down to a P80 = 45 ltm (80 per cent of particles passing 45 ¦rn. Conventional flotation cells will produce a single rougher concentrate that will be reground to No

Jan 1, 1993

By L. R. Willmott

An ethanolamine purification unit for removing carbon dioxide and hydrogen sulfide from Firscher-Tropsch synthesis gas was installed at the Bureau of Mines synthetic liquid fuels demonstration plant at Louisiana, Mo. The unit was a surplus Radford Girbotol unit from the Missouri Ordnance Works modified for a capacity of 90,000 std. cu. ft per hour of synthesis gas at 450 p.s.i.g., operating pressure. The hydrogen sulfide loading of the feed gas was specified at 500 grains per 100 cu. Ft. The unit was designed by the Girdler Corp. and installed by the Koppers Co. Initial operations were conducted far 11 days in May 1951. Thereafter 7 additional runs were made, varying lo duration from 8 to 54 days. The last run was terminated on May 29, 1953, the total time the Plant wars in operation being 219 days.

Jan 1, 1956

By John F. Sulzbach, Donald K. Walker, John F. Abel

With the increasing military significance of the arctic, the U.S. Army Corps of Engineers' ice- tunneling research program has been instituted to determine the feasibility of excavating large under- ice openings. Such openings would provide for year- around storage of material and housing of personnel, independent of surface weather conditions. This unique ice mining operation has been carried on in the tunnels at Camp Tuto, Greenland, during the summers of 1955, 1956, 1957 and 1958 by the U.S. Army Snow, Ice, and Permafrost Research Establishment (USA SIPRE), Wilmette, Ill. Supervisory personnel for the tunneling projects principally have been civilian mining engineers and mining engineering students from Colorado School of Mines. They have been employed under contract between USA SIPRE and the Denver Research Institute (DRI) of the University of Denver, Denver, Colo. Laborers have been enlisted military personnel attached to the U.S. Army Polar Research & Development Center (USA PR&DC) , Ft. Belvoir, Va.

Jan 6, 1959

By Kazumasa Taguchi

At the Kakogawa works of Kobe Steel. Ltd., the agglomeration facilities are composed of a pelletizing plant and sintering plant. This aim is to utilize raw materials efficiently and stabilize the raw material resources. Therefore at Kakogawa works, the blast furnaces (BF) have been operated with high pellet ratio and various developments for pellet properties have been achieved to improve the blast furnace performance. These developments include dolomite-fluxed pellets, new-porous pellets and crushed pellets. As a results of these improvements, pellets have achieved almost the same performance as sinter at high temperature regarding properties such as the softening, melting and reduction behaviour. However, some problems on shape have remained to be solved. Spherical pellets flow easily into the center of the furnace and form mixed layers of pellets and cokes. Therefore, in BF operations with these pellets it becomes more difficult to keep proper and stable gas distribution.

Jan 1, 1983

By K. E. Brown, A. R. Hagedorn

A 1,500-ft experimental well was used to study the pressure gradients occurring during continuous, vertical, two-phase flow through 1-in., 1 1/4-in. and 1 1/3-in. nominal size tubing. The test well was equipped with two gas-lijt valves and four Mathak electronic pressure transmitters as well as with instruments to measure the liquid production rate, air injection rate, temperatures and surface pressures. Tests were conducted for widely varying liquid flow, rates, gas-liquid ratios and liquid viscosities. From these data, an accucrate pressure-depth traverse was construcred for each test in each of the three tubing sizes. From the results of these tests, correlations have beer] developed which allow the accurate prediction of flowing pressure gradients for a wide variety of tubing sizes, flow conditions, and liquid properties. Also. the correlations and equations which are developed satisfy the necessary condition that they reduce to the relationships approprate to single-phase flow when the flow rate of either the gas or the liqutid phase becomes zero. All the correlations involve only dimensionless groups. which is a condition usually Sought for in similarity analysis but not always achieved. The correlations developed in this study have been used to calculate pressure gradients for pipes of larger diameter than those upon which the correlations are based. Comparisons of these calcuclaed gradients with experimetally determined gradients for the same flow conditions obtained from the literature indicate that extrapolation to these larger pipe sizes is possible with a degree of accuracy sufficient for engineering calculations. The extent of this extrapolation can only he determined with additional data from larger pipe diameters. INTRODUCTION The accurate prediction of the pressure drop expected to occur during the multiphase flow of fluids in the flow string of a well is a wideiy recognized problem in the petroleum industry. The problem has been brought even more into prominence with the advent of tubingless or slim-hole completions which use small-diameter tubing. Many of the correlations which give reasonably accurale results in the lager tubing sizes are greatly in error when applied to small-diameter conduits. Small-diameter conduits are defined as 1 1/2-in. nominal size tubing or smaller. The study of the pressure gradients which occur during multiphase flow of fluids in pipes is exceedingly complex because of the large number of variables involved. Further difficulties relate to the possibility of numerous flow regimes of widely varying geometry and mechanism and the instabilities of the fluid interfaces involved. Consequently, a solution to the problem by the approach normally used in classical fluid dynamics based on the formulation and solution of the Navier-Stokes equation has not been forthcoming. This is primarily the result of the nonlincarities involved and the difficulty of adequately describing the boundary conditions. As a result of the foregoing, most investigators have chosen semi-empirical or purely empirical approaches in an efford to obtain a practical solution to the problem. Much of the previous work in this area was done in short-tube models in the laboratory. A number of problems arise, however, when attempts are made to extrapolate these laboratory results to oilfield conditions where a much longer tube is encountered. In those few studies where data taken in long tubes were utilized, the data covered only a limited range of the variables, and as a result inaccuracies are introduced when the correlations are extended outside the range of the original data. Also, as a consequence of the limited amount of data available for these studies, the effects of several important variables were overlooked. The problem of predicting the pressure drop which occurs in multiphase flow differs from that of single-phase flow in that another source of pressure loss is introduced, namely, those pressure losses arising from slippage between the phases. This slippage is a result of the difference between the integrated average linear velocities of the two phases, which in turn is due to the physical properties of the fluids involved. In contrast to single-phase flow. the pressure losses in multiphase flow do not always increase with a decrease in the size of the conduit or an increase in production rate. This is attributed to the presence of the gas phase which tends to slip by the liquid phase without actually contributing to its lift. Many investigators have attempted to correlate both the slippage losses and the friction losses by means of a single energy-loss factor analogous to the one used in the single-phase flow problem. In an approach of this type, hourever, many of the important variables, such as

Jan 1, 1966

By F. A. G. M. Camisani-Calzolari

The uranium production forecasting program described in this paper projects production from Reasonably Assured, Estimated Additional and Speculative Resources in the cost categories of less than $130/kg U. Originally designed to handle South African production, it has been expanded and redimensioned using available published information to forecast production for countries of the Western World. The program forecasts production from up to 400 plants over a period of fifty years and has built-in production models derived from documented historical data of the more important uranium provinces. It is particularly suitable to assess production cavabilities on a national and global scale where variations in outputs for the individual plants tend to even out. The program is aimed at putting the uranium potential of any one country into a realistic perspective, and it could thus be useful for planning purposes and marketing strategies.

Jan 1, 1987

By P. H. Turnock, R. D. Pehlke

The effects of mutual interactions between elements on the solubility of nitrogen in liquid iron alloys containing chrormium, columbium, molybdenurn, nickel, or silicon have been determined. The equilibrium nitrogen solubilities in the liquid iron alloys were measured by the Sieverts method. The second-order effects caused by the presence of chrormium, columbium , or silicon in the melt were found to be significant. The solubility of nitrogen in liquid iron alloys containing several alloying elements has also been measured as a function of melt temperature and nitrogen pressure. The heat of solution of nitrogen in microcomponent iron alloys has been found to be a function of the logarithnz of the activity coefficient of nitrogen, irrvespectilje of the composition of the melt. The heat of solution of nitrogen in pure liquid iron was determined to be 1265 ± 450 cal per g-atom of N over the temperatxue range 1600° to 1800°. Sieverts ' law was obeyed for all melt compositions studied in the pressure interval 0.4 to 1.0 atm. The solubility of nitrogen in liquid pure iron and in many dilute binary liquid-iron alloys has been the subject of many investigations. Pehlke and Elliott' made a comprehensive investigation on this subject in which they summarized and compared previous researches. However, the practical application of these solubility studies requires prediction of the nitrogen solubility in the multicomponent alloys encountered in operating practice. The interaction parameter as defined by wagner2 has been used to predict the behavior of a solute in a complex alloy, and a modification of this approach has met with reasonable success in several instances.'1"5 The necessity for extending the nitrogen solubility data on binary alloys is caused by the lack of direct measurements of the solubility of nitrogen in molten alloy steels. A direct comparison between measured solubilities and those predicted for multicomponent alloys based on data in binary systems has been made in only a few instances, and most of these were reviewed by Langenberg,6 who developed a graphical technique for predicting nitrogen solubilities in multicomponent iron alloys. The solubility of nitrogen has also been studied over the entire Fe-Cr-Ni ternary system by Humbert and Elliott.? Both studies compared the solubilities computed from binary iron alloy data with those measured in ternary alloys in the liquid state at 1600°C. Most of the nitrogen solubility measurements referred to above were for iron alloys at 1600°C; thus, the ability to predict nitrogen solubilities in molten iron alloys has been restricted primarily to alloys at 1600°C. Recently, Nelsson8 devised an approximate method for calculating the change in nitrogen solubility in molten iron alloys as a function of temperature, but an assumption of regular solution behavior limits the applicability of the method. Chipman and Corrigan9,10 have developed an empirical correlation. based on the activity coefficient of nitrogen in the iron alloy at 1600°C, which facilitates the estimation of nitrogen solubilities at higher temperatures. This method also has limitations, due to the necessity of calculating the activity coefficient for nitrogen in a multicomponent iron alloy at 1600°C from the nitrogen solubility data for binary iron alloys. The shortcoming of such a straightforward approach to the problem of predicting nitrogen solubilities is the disregard of mutual interactions between elements in a complex iron melt. This investigation was conducted in an attempt to provide a more reliable method of predicting nitrogen solubilities in multicomponent iron alloys. The effects of the mutual interactions between chromium, nickel, silicon, molybdenum, or columbium in iron were studied, using the Sieverts' technique1,7 to measure the effects of alloy composition, temperature, and pressure on the solubility of nitrogen in ternary liquid iron alloys.

Jan 1, 1967

By A. M. Anthony, A. Y. Atta, S. S. Magaji, U. Abubakar-Zaria

There are two major gold recovery methods: the hydrometallurgical technique, which employs cyanide solutions, and amalgamation method, which involves mercury (Hg). These methods present considerable health, safety, and environmental concerns. Past applications of alpha-cyclodextrin (α-CD) on gold scraps show that α-CD is not only inexpensive, but is also environmentally friendly. This research work used α-CD to recover gold from gold ores instead of gold scraps. The gold ore was sourced from Shanono gold deposit site Kano State,Nigeria. The gold ore was characterized by fire assay (FA) for the precious metal. The concentrate was digested with aqua regia (AR) for 24 h. Modified AR, where hydrochloric acid was replaced with hydrobromic acid, was used for the gold digestion due to the good match in molecular recognition between gold bromide ion (AuBr)− and α- CD in a second sphere coordination complex. The digestate was characterized using atomic absorption spectroscopy (AAS). Gold recovery using this technique is pH sensitive, and five pH values (2.0, 3.6, 4.0, 5.4, and 6.0) were investigated. FA analysis showed the Shanono gold ore deposit contains an average of 4.71 ppm of gold, AAS analysis showed highest gold recovery of 69% at pH 4.0, which is lower than recoveries from the metal scraps. This could be due to the presence of other gangue minerals closely associated with the ore. However, gold recovery using α-CD on Shanono gold ore has shown to have a higher yield of 69% compared to 35.5% yield obtainable by Artisan Small Scale Miners using mercury.

May 5, 2020

By A. E. Harnsberger

IT is obvious that details such as the physical and chemical properties and methods of heat-treating of the materials mentioned must be omitted in a paper on the subject of materials used in oil-refinery pumps1. Only sufficient identification is given to enable the reader to find additional information from already published data. Also, the subject covers many operating conditions, but only the most important services can be discussed here. To the oil refiner, the pumping equipment is of vital interest. Practi-cally every refinery operation, from the charging of crude oil to a dis-tillation unit to the shipping of refined products, involves some form of pumping machinery. Intermediate refining stages involve a great variety of pumping machinery to carry out successfully the aims of the refinery technologist. Temperatures at which oils are handled vary from -50° F. to 900° F. Pressure may vary from subatmospheric to 2000 lb. per sq. inch. The selection of the proper materials involves a careful consideration of the conditions under which the particular pump must operate. The four most important considerations are temperature, pressure, corrosion, and abrasion or wear. Consideration of temperature "may be divided into three parts: (1) extremely low temperatures of the order of -50° F.; (2) temperatures at atmospheric or slightly above; (3) temperatures from 200° to 900° F. Pressures fall into two groups: (1) pressures reached by ordinary trade pumps of the order of 200 lb. per sq. in., (2) extreme pressure conditions involving pressures as high as 2000 lb. Noncorrosive and corrosive oils can be treated differently. Under the latter falls corrosion in the presence of water, which will occur up to 250° F. The second type of corrosion occurs in high-temperature pump-ing equipment, with temperatures from 450° to 900° F., largely caused by sulfur compounds. There are also other corrosive conditions met with

Jan 1, 1935

By Robert J. Evans

Capital and operating costs were estimated using a wet suppression, fabric filter, and a combination system of the two for hypothetical hard rock stone crushing plants located in central Pennsylvania, operating at 300, 600, and 1,000 tons per hour. Fixed capital expenditure for the dust abatement systems ranged from $49,129 to $249,162. Annual operating costs for the dust abatement systems ranged from $8,394 to $46,606 (0.9 to 3.2 cents per ton). If these dust abatement systems are properly sized, installed, and maintained, efficiencies approaching 95 percent can be expected for reduction in weight of dust particles emitted before control.

Jan 1, 1975

The Australian Coal Combustion Testing and Research Facility has been operating commercially for one year and during that period coal product evaluations have been conducted on behalf of four coal companies and one electricity commission. The facility is equipped to assess the behaviour of steaming coal in milling, combustion (including flame stability, burnout and heat transfer), ash deposition and erosion, fly ash collection and gaseous emissions. The relevance of the results of the pilot testing to industrial practice was demonstrated during the calibration of the facility using four coals burnt in Australian power stations. The calibration coals were from the Tarong and Gladstone Power Stations in Queensland, tluja Power Station in Western Australia and Bayswater Power Station in New South Wales. Also an opportunity arose to visit an overseas power station to observe a full scale test burn using one of the early coals tested on a commercial basis in the combustion test facility. The calibration trials showed excellent agreement with industrial coal performance in t:orms of flame stability, turndown, carbon burnout and gaseous emissions. Encouraging correlations were also found in the case of furnace radiation, boiler deposits (slagging and fouling) and electrostatic precipitation. In the case of the last group the only real reservations about the correlations are due to the non-availability or qualitative nature of results collected around the power stations. In all cases there is a high degree of confidence in the facility's ability to predict the relative performance of different coals and in some cases direct numerical predictions can be Made.

Jan 1, 1987

By Evan Just

Government aid, regulation, and participation in the mineral industry are not new; they date back to the time when man first adopted communal living. Even in primitive tribal life, the obtaining of arrowhead or ceramic materials, washing of gold, or mining of copper were specialized activities, under tribal sponsorship. Later, when kingdoms, dynasties, and hierarchies developed, titles to mining properties were held by the sovereign or the state, work usually being done by slaves. Title acquisition through denouncement developed in Europe in the late Middle Ages and spread to the Western Hemisphere with the Spanish and Portuguese empires. Denouncements still recognized the rights of the sovereign in the requirement to pay royalties, which practice continues in many places today. Thus, anyone who views government participation in mineral activity as "encroachment" has no historical perspective. Only in a few countries and for a few generations have private interests enjoyed the right to exploit mineral deposits without the specific consent of the sovereign or without payment of royalty. Governments and the mineral industry have been linked together by other factors. Governments have had special interest in metals and minerals as stores of value and for armaments. Spanish conquests in the New World were energized by the lure of gold and silver. Pursuit of gold led to the American seizure of California in the days of the Forty-niners. The strategic importance of minerals in our own times has called for special steps to stimulate production in national emergencies and to prevent the enemy from acquiring mineral supplies. Our export controls to deny certain minerals to unfriendly countries, purchases for Government stockpile, and subsidies for domestic production are examples. Production regulation by state governments of oil and gas has become a well established routine. In brief, the mineral industry has never lacked aid, regulation, and participation by governments. The entrepreneur who wishes to explore for or develop minerals must deal with governments in most areas before he can begin, because mineral rights are reserved by them. He can proceed through discovery and de-

Jan 1, 1964

By C. K. Leith

GENERAL GEOLOGY OF THE LAKE SUPERIOR IRON-BEARING AND COPPER-BEARING SERIES. THE geology of the Lake Superior region is of general interest, both from an economic and a scientific standpoint. The presence of large and rich iron- and copper-deposits has made a knowledge of the geology of the region necessary for purposes of exploitation and exploration. The ores of the region are contained in rocks of pre-Cambrian age, 'pith for most of the country up to recent years have usually been referred to as « crystalline schists " or " crystalline complex;" and regarded principally as metamorphosed basement-unit upon which the sedimentary rocks, beginning with the Paleozoic, were laid down. In the Lake Superior re¬gion this pre-Cambrian complex presents an unusual variety of rocks with determinable relations. It has been possible, with the large expenditures which-the magnitude of the iron-mining industry warrants, to work out their stratigraphy to a larger extent than has been possible in almost any other area of pre-Cambrian rocks. The real complexity of Lake Superior geology, the confusion of names and the multiplicity of reports covering small parts of the region, are such that interested persons, other than. geologists directly engaged in the work, may well hesitate to attempt to comprehend the geology of the region as a whole. The following paper is a somewhat elementary outline of the geology of the Lake Superior region with special reference to new developments not yet covered in published reports. Geological information concerning the region has been gath¬ered by mining companies, and by the geological surveys of Michigan, Wisconsin, Minnesota, Ontario, Canada, and the United States.. Perhaps in no other part of the country have the mining men themselves spent such large sums in purely geological work. This has made possible the publication of ,reports and maps by the State and Government surveys in much less time and at far less cost than would have been otherwise possible. The. U. S. Geological Survey is the only organization which has covered all of the region on the United 'States side of the boundary, and as its reports include the in¬formation gathered by the mining companies and State organi

Mar 1, 1905

By J. G. Russell

The valuation of known mineral re-serves entails the economic evaluation of the mining enterprise and the valuation of other assets employed, including mining and processing plant and intangible assets. A case study approach analyzes two reserve situations: ownership of reserves (phosphate rock), and leasing of reserve lands (kaolin). The appraisal of the physical property is outlined, along with the economic analysis of the operation. The discounted net cash flow approach is used to value the enterprise, leading to value of the reserves after correlation with other assets employed.

Jan 1, 1989

By Louis Tellier

SIDBEC commenced detailed planning of major capital expenditures to install integrated steelmaking facilities in 1969. Today, less than IO years later, SIDBEC and its subsidiaries have completed major mining, concentrating, pelletizing, direct reduction ? electric furnace steelmaking and continuous casting plants. The total cost of these projects was almost 1 billion dollars. The philosophy behind the project planning and the evolution of management control are explained. These extensive projects were undertaken during a period of exceptional inflation and a disturbed labour climate, but were nevertheless completed with only modest overruns, with good control of timetables and with exceptionally good start-up performance. Project planning, relations with consulting engineers, introduction of new technology, purchasing and field management and cost control are discussed.

Jan 1, 1979